Vol. 18, issue 05-06, article # 4

Abstract:

Using the data of measurements in 2001-2004 at the Zvenigorod Station of the Institute of Atmospheric Physics, variations of three basic characteristics of the near-surface aerosol are analyzed: the mass concentration M, the Angstrom exponent a, and the parameter of the condensation activity c. Based on the data collected in the previous decade, it is shown that the decrease in the annual mean value of M, lasting for about a decade in Central Russia, has stopped in the beginning of this century, and its gradual increase for the past three years is observed. This is caused by a decrease observed in the frequency of occurrence of the cases with very low M values and an increase in the frequency of occurrence of the cases with very high, up to 250 mg/m³, M values. Power spectra of aerosol parameters are analyzed. In addition to the well-known variation periods of ~ 5, 7, 10, and 45 days, the periods of about 14, 20, and 90 days have been revealed. The wavelet analysis performed has shown that variations group as time-limited series, and the periods and the amplitudes of the oscillations within the series do vary. It is shown that the long-period variations may be predominantly of the concentration origin when there is no relation between M and the Angstrom exponent during long time intervals, or may be due to changes in the mean particle size. Time intervals up to several months long have been revealed, which are characterized by high anti-correlation between M and c (the absolute value of the correlation coefficient > 0.7).